In order to form a SiC semiconductor device, it is necessary that an epitaxial layer serving as an active region of a semiconductor element is caused to grow on a SiC substrate. The epitaxial layer is formed through step-flow growth. A crystal surface of the SiC substrate has a fine unevenness, and an uneven portion is called a “step” while a surface having no uneven portion is called a “terrace”. In the step-flow growth, a wafer is inclined so that reactive species adhering to the crystal surface diffuse over the terrace, and the reactive species are sequentially incorporated from the one having reached the step. Thus, a flat surface morphology is obtained. Generally, the inclination of the wafer is formed in the [11-20] direction from a (0001) plane. An angle of the inclination is called an “off angle”. Currently, the general off angle is 8 degrees in a case of a 4H-SiC substrate, and 3.5 degrees in a case of a 6H-SiC.
Patent Document 1 proposes to cause an epitaxial growth on a 4H-SiC substrate having an off angle of 8 degrees from a (0001) plane of the substrate in the [11-20] direction, to thereby form an epitaxial layer on which an epitaxial growth is further caused at a raised growth temperature, thus reducing the Basal Plane Dislocation density that is taken over from the SiC substrate.